18
ASYNC SHORT-HAUL MODEM MP
Symptom:
LEDs do not light when the AC power transformer is plugged into
the wall outlet.
Problem 1:
The AC transformer is not plugged into the Modem.
Solution 1:
Plug in the transformer.
Problem 2:
Loose power connection.
Solution 2:
Make sure the AC connection is flush.
Problem 3:
Outlet is defective.
Solution 3:
Try a different outlet.
Problem 4:
AC power adapter is defective.
Solution 4:
Call for a replacement adapter.
Symptom:
No data transfer in either or both directions.
Problem 1:
Improper twisted-pair wiring.
Solution 1:
Compare your twisted-pair wiring with the diagram in
Section 4.1
.
Problem 2:
Improper DCE/DTE setting.
Solution 2:
Set both DCE/DTE switches alike, according to the instructions in
Section 3.2
.
Problem 3:
Improper bit-rate setting.
Solution 3:
Be sure all bit-rate settings on all connected serial ports are the
same.
Problem 4:
Improper “control input” pin setting.
Solution 4:
The transmitter must be enabled by a specific “control input” pin
(refer to Table 3-1 in
Section 3.3
).
Problem 5:
Distance specifications exceeded.
Solution 5:
Check specifications in
Appendix A
.
